Electrical connectors of the plug-in type which utilize elastomeric material inserted in the connector to improve contact and longevity of the connector are well known in the art. These utilize various geometries and methods of insertion of the elastomeric material as set forth in the prior art known to inventor below.
Smith, U.S. Pat. No. 2,502,634 teaches the use of cylindrical shaped resilient material in connection with a split core of the female member to improve the contact with the male.
Camzi, U.S. Pat. No. 3,031,641 is likewise directed to improvements in the female member of the connector by utilizing a special slotted hollow construction to provide elastic action of the metallic members.
Dorell, U.S. Pat. No. 3,871,737 utilizes a conductive elastomeric material in a housing to which the male member is inserted, the material being displaced by the insertion to surround the male member and provide improved contact.
Schlesinger, U.S. Pat. No. 3,853,377 teaches several applications of an elastomeric material both internal to the male member and external to the female member and is especially adapted for electrical panel boards and the method of introduction of the elastomeric material is such as to preclude its expansion under pressure which is a difficulty which I overcome using my method of manufacture.
British Pat. No. 739,472 comes close to mine in that it teaches a cylindrical shaped rubber insert between two connecting limbs in such a manner as to provide opportunity for the rubber to expand when under pressure while improving the contact of the limbs. It is, however, limited to the particular cylindrical geometry of the overall plug connector.
British Pat. No. 929,674 teaches the use of a nylon insert which is split into sections, the resilience of which tends to aid retention of the inserting pin. The insert in this case is likewise confined so as to limit its expansive opportunities and hence its flexibility. It is likewise limited to the geometry which it teaches which is far different than that of mine.
Plugs comprising cylindrical prongs split through the center as illustrated herein have many advantages but the insertion of an elastomeric material in the slots to increase the efficiency has met with difficulties and has not been effected properly until the invention of my process as covered herein.
All previous devices using an elastomer to prevent deformation and improve contact require vulcanizing the elastomer after insertion necessitating expensive and time consuming moulding plus expensive placement of the inserts.
Should there be other than a secure tight connection when used electrically under load, the loose connection can be cause for internal arcing between the two loose surfaces. This causes less so called good conducting contact until the area spreads to such an extent that the metal reaches temperatures high enough to anneal the metal and causes further oxidation on the surface.
If copper is present, such as in brass, the oxide formed is copper oxide, which is a rectifier, causing more heating and deteriorating of the surfaces through resisting the passage of the current. The units covered with this oxide should not be scraped, because if this is scraped off after it has cooled down an even looser fit will result starting the cycle all over.
Causes of lessing of electrical contact area are:
Repeated improper making and breaking contact where the connector is severely "wriggled" to open the connection, making and breaking under load, etc., dropping or stepping on the male connector, hitting the pin, contamination through paints, dirt, etc. Using a knife blade to open up the compressed slot has been considered acceptable where light loads are used. Constant uses can eventually cause the side of a pin to break off. Considering time, material and effort, plus down time, it gets to be a pretty expensive detail.